Physicochemical properties and composition of ginsenosides in red ginseng extract as revealed by subcritical water extraction

Red ginseng was treated by subcritical water extraction (SWE) whose two parameters were the extraction temperature (105-150oC) and time (5-20 min) under a high pressure. The oBrix value, solid content, color difference, and turbidity of the red ginseng extract increased with increasing extraction time and temperature, while the pH decreased. The total concentration of ginsenosides in the red ginseng extract was maximal at 120oC and 20 min. The concentrations of ginsenosides Rg3 and Rh1 were maximal at 150oC and 15 min. The concentrations of Rg3 and Rh1 were respectively 3.5- 5 times and 2-2.5 times higher than those treated by conventional extraction methods with hot water, ethanol, and methanol. SWE is a particularly effective method for the selective extraction of less-polar ginsenosides such as Rg3 which is well known to exert strong anticancer effects.